>>8 Not necessarily. The person hasn't listed how long the happiness or anger lasts. In the case that these periods don't last a few weeks or longer at a time, they are not bipolar. From the way the person speaks about this issue, it seems like it changes much more frequently than that. In that case, I would say it might be Borderline Personality Disorder.
That being said, I am definitely not qualified to diagnose anyone, nor did the person provide nearly enough information for anyone to be sure, so it would be better if they didn't draw any conclusions for the time being. Maybe it's a good idea to go to someone who is qualified, if it's worrying.